Ultrafine Scaly Crystal Tungsten Disulfide and Its Preparation

Tungsten disulfide is a fine gray crystalline or powder with metallic luster. It belongs to hexagonal crystal system. It has semiconductor and diamagnetic properties, layered structure, easy dissociation, and lubricating properties similar to graphite. It is mainly used as lubricant. Its performance is better than molybdenum disulfide. Its friction coefficient is lower and its compressive strength is higher.

The production methods of tungsten disulfide include ammonium tetrathiotungstate oxidation roasting decomposition method and acidification thermal decomposition method. However, the purity of tungsten disulfide produced by the above two methods is low, and the crystal structure is not hexagonal, which can not meet the market demand for ultra-fine squamous tungsten disulfide with high purity and hexagonal crystal structure.

In addition to oxidation roasting decomposition method and acidification thermal decomposition method, Baidu Encyclopedia also introduced a superfine scaly crystal tungsten disulfide, which is known to have the best lubrication performance. The preparation of ultra-fine scale crystal tungsten disulfide is based on ammonium tetrathiotungstate as raw material, decomposes ammonium tetrathiotungstate by heating under the condition of insulating air, and then produces the target product by heating, constant temperature and annealing processes. The specific operation is as follows:

Using ammonium tetrathiotungstate with 5% water content and 0.03% impurity as raw material, the fineness of ammonium tetrathiotungstate is less than 460 m (more than 40 meshes). The raw material ammonium tetrathiotungstate is placed in an electrolytic calciner to insulate the air for closed incubation. The temperature gradient is 114.5 ℃/h, from room temperature to 1120 ℃, after keeping constant temperature for 27 hours at 1120 ℃, the temperature is 47.3 ℃/h. The purity of tungsten disulfide is 99.63% and the fineness is 2-20 microns. It is hexagonal tungsten disulfide with ultra-fine scale shape. The fineness is 2-20 microns and the purity is 99.50-99.99%.

Ultrafine scaly crystal tungsten disulfide has higher heat resistance, high pressure resistance and lubricity. It can be used as lubricant for high speed, high pressure, high vacuum and high temperature or low temperature abrupt change parts.

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